patient compliance

Patient compliance is how faithfully a patient actually takes a medicine as prescribed — the right dose, at the right times, for the full course. The best drug in the world fails if it stays in the bottle, and in practice a large fraction of patients miss doses, stop early or take them wrongly.

Dosage-form design strongly influences compliance. A bitter, hard-to-swallow tablet taken four times a day is easy to skip; a pleasant once-daily tablet is far easier to keep up. This is why pharmaceutics works on taste-masking, smaller tablets, simpler schedules and sustained-release forms that cut dosing frequency.

The word compliance is increasingly replaced by adherence or concordance, which frame the patient as a partner rather than someone simply obeying orders. Either way, understanding why patients do not take medicines — cost, side effects, complexity, forgetfulness — is essential, because formulation can solve some of these problems but not all.